The default position of the gauge is full when there is no current to the gauge. You have a bad ground or a bad circuit to the gauge. Your sending unit is a 30 ohm unit. 30 ohms resistance is a full tank. With no current you are getting full resistance therefor a full reading on your gauge.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.